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Spectroscopy

Spectroscopy . Spectroscopy on Charmonium and D-mesons Adrian de Nijs Student seminar on subatomic physics. Contents . Motivation Quark mass Experiment Charmonium spectrum D-meson spectrum Summary and Outlook. Motivation. CKM-parameter determination QCD-test D 0 -D 0 oscillations.

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Spectroscopy

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  1. Spectroscopy Spectroscopy on Charmonium and D-mesons Adrian de Nijs Student seminar on subatomic physics

  2. Contents • Motivation • Quark mass • Experiment • Charmonium spectrum • D-meson spectrum • Summary and Outlook

  3. Motivation • CKM-parameter determination • QCD-test • D0-D0 oscillations

  4. CKM-Matrix • State mixing between quarks • Lepton univerality • d’= d cos θc+ s sinθc s’= -d sinθc+ s cosθc Cabbibo angle θc≈13° • Mixing of the order of 5% between lepton families

  5. CKM-Matrix • Kobayashi and Maskawa extended to 3x3 • 2008 Nobel Prize • Vcb from

  6. Quark Mass • Model dependent • Constituent masses from hadron masses • Possible to find current quark mass differences

  7. Quark Mass • m-mΔ ≈mΞ-mΣ ≈mΩ-mΞ ≈ 150 MeV • ms-md ≈ 150 MeV • Steps in U3

  8. Quark Mass • + (1189 MeV) = (uus) • 0 (1193 MeV) = (uds) • - (1197 MeV) = (dds) • 3 Mass contributions: M=M0+mi+eiej • eu =⅔ ed=es=⅓

  9. Quark mass • M(+)=Mo+2mu+ms+(eued+eues+edes) • M(0)=Mo+mu+md+ms+(eueu+2eues) • M(-)=Mo+2md+ms+(eueu+2edes) • M(-)+ M(0)-2 M(+)=3(md-mu)+(⅓-⅓+0) • 12 MeV = 3(md-mu) • md-mu≈4 MeV • In a similar way: ms-md≈150 MeV

  10. Quark Mass • Similar for Charm: • MB-MD≈mb-mc≈MΛb-MΛc • ΛQ=(Qqq) • B=(bq), D=(cq) • mb-mc≈3.4 GeV

  11. Experiments • One example: Cleo • Electron-Positron collisions • Formation experiments: Precise beam energy to create the wanted state

  12. Detection • Different kinds of charged/neutral particle detectors • Complex data analysis

  13. Charmonium Spectrum • Most states found are 1-- • J/Ψ discovered in 1974 by two groups

  14. Charmonium Spectrum • Hyperfine splitting: mass difference between 11S0 and 13S1 • Difference smaller in bottonium • Widths above threshold far wider due to OZI rule

  15. K- K+ 0 e- e+ OZI or Zweig-rule • Φ-meson can decay to K-K+ or π+π0π- • 3π decay needs 3 gluons, suppressed

  16. Charmonium Spectrum • Lattice comparison • Quenched approximation • Gauge coupling parameter  • ΔM(13S1-13S1)=85.3(4.4)(+5.7)(-2.5) ΔM(13S1-13S1)=117.1(1.8) • Not very good, main features present • 13S1-13S1 sensitive to lattice calculation choices • Not really possible to have a good QCD test

  17. Charmonium spectrum • Four more states expected below threshold • Difficult to find, long cascades with small branching ratios • B →Kηc2 →Kγ(280MeV)hc → Kγ(280MeV) γ(500MeV)ηc • Found by CLEO

  18. D-meson Spectrum • Baryon decuplet • Ortho and Para states • D=(cq) • Ds=(cs) • D*: Para state

  19. D-meson Spectrum • Newly found narrow states • Found by two experiments • Some problems with identification

  20. D-meson spectrum • Natural interpretation as 0+ and 1+ states • D*s0+(2317) and D*s1+(2460) • Gives the right decays and widths • Problems: • No other decay modes found • Masses far below predictions • Corresponding non-Charm resonances not found

  21. D-meson Spectrum • Other explanations: • DK molecule • Cannot explain small widths • Coupling between parity pairs (Ds,D*s) and (D*s0+, D*s1+) • Mass splitting between doublets: • ΔM=M(D*s0+)-M(Ds)≈ M(D*s1+)-M(D*s)≈mN/3

  22. D-Meson Spectrum • Finding states in data: • Find decay channel • Combine decay products • D*SJ→D+Sπ0→Φπ+π0 →K+K- π+π0

  23. D-Meson Spectrum • D*SJ→D+Sπ0→Φπ+π0→K+K- π+π0

  24. Summary • Motivation: • CKM-parameter • QCD-test • D0-D0 oscillation • Quark mass • Cleo • Charmonium • Hyperfine splitting • Lattice comparison • Recently found states • D-Meson • Newly found narrow states • How to find states

  25. Outlook • QCD-Test • Better lattice calculations • CKM-parameter • Better knowledge of the b,c masses • Narrow D-Meson levels • Finding these levels for non-strange D-mesons

  26. Liturature • A Cicerone for the physics of charm S.Bianco et al, 2003 • Observation of a narrow meson decaying to D+sπ0 at a mass of 2.32 GeV/c2 B.Aubert et al, 2003 • Charmonium spectrum from quenched anisotropic lattice QCD M. Okamoto et al, 2002 • B-Meson gateways to missing charmonium levels E.J.Eichten, K.Lane and C.Quicg, 2008 • Nuclear and Particle Physics by W.E.Burcham and M.Jobes

  27. Thank you for your attention • Any questions? .

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